In accordance with the variety of needs in cosmetics, various research and developments have been performed for powdery components such as pigments to be used in cosmetics. In particular, for powders for cosmetics, many types of surface treatments or composite powders have been proposed. For example, JP-A-H06-1709 discloses composite pigments comprising a core particle covered by fine particles of an inorganic UV filter.
The composite pigments based on fine particles of an inorganic UV filter can provide good UV filtering effects for the UVB region (260-320 nm in wavelength). However, the UV filtering effects provided by these composite pigments based on inorganic UV filter(s) are insufficient in the UVA region (320-400 nm in wavelength).
On the other hand, composite pigments including fine particles of solid organic UV filter(s) have not yet been proposed.
Fine particles of solid organic UV filters can easily aggregate and have poor dispersibility. Therefore, it is often difficult to uniformly disperse the fine particles of solid organic UV filters in the form of primary particles in cosmetics. Therefore, the UV filtering property of the cosmetics including fine particles of solid organic UV filter(s) is difficult to be enhanced.
Further, there are some risks that fine particles of solid organic UV filter(s) may penetrate into the skin via pores on the skin, which may give adverse effects on the skin because the barrier property of the skin is not strong in pores, and that solid organic UV filter(s) when it or they irritate can easily contact with the skin, which may also give adverse effects to the skin.